Do-ers do, as a matter of preference. So, as MAIN CHARACTERS, they tend to always want to do. However, they are part of the Overall Story as well, and if it is a Decision driven story, they're going to feel like a fish out of water. So I think the answer to your question is to make sure your Do-er is in a Decision driven story in order to make him or her frustrated by the lack of "doings" effectiveness.

What would they do if they "spit the dummy" (e.g. showed a sudden display of anger or frustration)? Why, they would DO something about it. Throwing things, beating on things, doing exercises, running, whatever so long as it involves some sort of physical activity.